Dam having an internal apron and means for indicating leakage of apron

ABSTRACT

A dam having a core packing providing a sealing apron, laterally supported by upstream and downstream embankments, and vertically supported by a foundation toe wall, is provided with means for detecting the location of leaks in the sealing apron. A filter wall vertically supported by the toe wall is laminated with the core packing, for receiving leakage of the core packing at about the location where leakage occurs. A plurality of leakage water collectors are disposed in the toe wall, and the collectors are communicated, respectively, with different sections of the filter wall. The location of leaks can be detected by observation of water received at the collectors.

United States Patent 1 1 1 3,779,022

Feiner 5] Dec. 18, 1973 [54] DAM HAVING AN INTERNAL APRON AND 1,997,132 4/1935 Collorio 61/31 MEANS FOR INDICATING LEAKAGE OF FOREIGN PATENTS OR APPLICATIONS APRON 1,263,625 3/1968 Germany 6l/3l Inventor: Alfred Feiner, Porz-Westhoven,

Germany Assignee: Strabag Bau-A.G., Cologne-Deutz,

Germany Filed: Feb. 24, 1972 Appl. No.: 228,865

Primary Examiner-Jacob Shapiro Attorney-Ralph D. Dinklage et al.

[57] ABSTRACT A dam having a core packing providing a sealing apron, laterally supported by upstream and downstream embankments, and vertically supported by a foundation toe wall, is provided with means for detect- Foreign Application Priority Data ing the location of leaks in the sealing apron. A filter Mar. 9, 1971 Germany P 21 11 034.9 wall vertically supported by the toe wall is laminated i with the core packing, for receiving leakage of the [52] [1.8. CI. 61/31 core packing at about the location where leakage oc- [51] Int. Cl E02b 7/04 curs. A plurality of leakage water collectors are dis- [58] Field of Search 61/31, 33, 32, 3O posed in the toe wall, and the collectors are communi- 1 cated, respectively, with different sections of the filter [56] References Cited wall. The location of leaks can be detected by obser- UNlTED STATES PATENTS vation of water received at the collectors. 3,167,923 2/1965 Lohr et al. 61/31 23 Claims, 10 Drawing Figures I k5 l k I y k7 14a 14b 14 b .1 X 150 I 1 k2 k3 3 19a 20 -d 19b 19c 18c WYENTED 53 1 3 973 SHEET 10F 3 PAI'EHTED in: is 1975 3779.022 SHEET BUY 3 Fig 10 1 DAM HAVING ANINTERNAL APRON AND MEANS FOR INDICATING LEAKAGE OF APRON BACKGROUND The invention relates to dams, particularly to a core packing provided'in the interior of a dam across a valley or similar dam andto the-checking of the imperviousness of such core packing.

For example, according to German Patent Specification No. 1,175,615, the imperviousness of core packings has hitherto been checked by means of control packingswhich are connected to the core packing. The control packings which extend in a direction transversely of the core packing into the downstream embankment of the dam are laid along the whole longitudinal dimension (i.e.', width) of the dam so as to slope in both directions of the dam, their lowermost points being connected to drain pipes for draining the leakage water collected in the control packings, the drain pipes emergingfrom the downstream face of the dam. The control packings are subdivided in the longitudinal direction of the dam into a plurality of control sections, the individual sections being so constructed that each control packing which is associated with the respective control section and provided with a support in the form ofa filter bed, and which slopes inthe longitudinal direction of the dam, extends below the respectively adjacent control packing of the next control section to the lateral end of the dam or to the middle of the dam, whence the leakage water collected in the individual control sections in discharged separately. These control packings extend into the dam to an extent sufficient to ensure that they cover at least the vertical projections of the overlying sections ofthe core packing. For this reason, they require a substantial expenditure for high quality buidling material for the packing andthey are also of a complicated construction. Moreover, they are subject to uncontrollable settling movements occurring in the downstream embankment of the dam, which settling movements apply un controllable transverse forces, particularly to their connection to the core packing. Such transverse forces may cut-off the auxiliary packing from the core packing and displace the slope or gradient of the auxiliary packing which thus become completely useless. It is virtually impossible for such damages to be repaired.

THE INVENTION Thus, the invention is directed to an improvement in a darn comprising a core packing providing a sealing apron, with upstream and downstream embankments laterally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing. According to the invention, provision is made for detecting the location of leaks in the sealing apron. A filter wall, vertically supported by the toe wall, is laminated with the core packing, for receiving leakage of the core packing at about the location where leakage occurs; A plurality of leakage water collectors aree provided in the toe wall, and the collectors are communicated, respectively, with different sections of the filter wall for receiving leakage, respectively, fromsaid sections. The location of leaks is then detectable by observation of water received at the respective collectors.

According to one aspect, the invention provides a core packing provided in the interior of a damor embankment, comprising one or more vertically extending filter beds or layers in the interior of the core packing for checking the imperviousness of the core packing, each filter layer or bed extending along the whole longitudinal dimension (width) of the core packing to form therewith an intimately interlocked uniform body which, in turn, is intimetely bonded with downstream and upstream embankments of the dam, each filter layer or bed resting on the upstream toe wall of the dam and being in communication with leakagewater drains.

According to another aspect, the invention provides a method of inserting a filter layer in a core packing during construction of a dam orembankment. The material used for the core packing and material used for downstream and upstream faces of the dam or embankment are progressively and simultaneously deposited spatially separately over the width of the dam using parallel vertical or inclined partitionsadvancing over the width of the dam. Horizontally extending layers are progressively laid and each such layer is levelled to substantially the same level. See US. Pat. No. 3,299,642. Material used for the filter layer or wall in the core packing is deposited together with the other building material within the core packing. Two substantially parallel vertical or inclined partitions within the first mentioned petition are used for the material for the filter layer or wall and the filter material is levelled to substantially the same level as the other building material. The fills of material for the filter layer or wall and the packing, which fills lie directly adjacent each other beyond the partitions in the direction of movement of the partitions, and the fills of the material for the lateral embankments, can be simultaneously compacted.

According to yet another aspect, the invention provides an improvement in apparatus for inserting a core packing in layers during construction of a darn or embankment, comprising two substantially parallel inclined or upright partitions which are spaced apart at a distance corresponding to the thickness of the core packing, means for feeding core material between the partitions, and means for depositing the building material for downstream and upstream faces of the dam externally of the partitions. The apparatus is moved back and forth over the width of the dam to build up succes sive horizontally extending layers of the materials. The materials are levelled as they are deposited. Reciprocating compacting devices for the simultaneous compacting of the separately deposited and levelled building materials are provided behind the partitions as considered in the direction of movement. See US. Pat. No. 3,299,642. According to the invention, further partitions extending parallel to the first mentioned partitions and to each other are provided, the second partitions being spaced apart a distance corresponding to the thickness of the filter wall, and means are provided for inserting and levelling the filter material between the second partitions. Also a compacting device capable of compacting the filter material simultaneously with the other building materials is provided.

The control system which comprises the filter wall and the leakage water drains provided in the upstream toe wall constitutes an integral, load-bearing unit which is largely insensitive to settling movements in the embankments on both sides, since it extends substantially vertically or inclined steeply through the dam and is securely supported by the upstream toe wall.

The control system, which may thus be subdivided into an optional number of vertical control sections aligned over the width of the core packing, may comprise a plurality of separate drainage compartments covered with gratings, in which and from which compartments the leakage water from various substantially vertical control sections of the core packing is collected and discharged, the compartments being provided in the upstream toe wall, that is to say, in the zone at the bottom of the valley in its upper supporting area, and in the area of the filter bed resting on that supporting surface.

The filter wall may be provided with horizontally extending sealing strips provided in the lower part of the filter wall, serving to convey leakage to a single location, whereby observation is facilitated.

Thus, sealing strips may extend in parallel substantially vertically spaced relation from both sides of the darn, at a gradient down to the lowermost, center point of the dam, their lengths being graded or stepped so that the lowermost sealing strip has the greatest length. This provides drainage channels extending between the strips which can be in communication with separate drainage compartments provided at the lowermost point of the upstream toe wall. The leakage water collecting between the individual sealing strips is separately collected and drained off. In this construction, all of the drainage compartments or chambers may be provided closely side by side at the lowermost position of the upstream toe wall where they may be readily checked from the downstream side or face of the dam, for example through a short inspection of observation tunnel.

For checking the core packing in a high dam, the vertical control sections are advantageously subdivided in one or more horizontal planes into superimposed par- 1 tial sections, and the leakage water collecting in the individual partial sections is advantageously separately collected and discharged. Thus leaks in the core packing may be located much more accurately than before and the work expended for sealing such leaks may be considerably reduced. The subdivision of the checking or control system into a plurality ofjuxtaposed, superimposed partial sections may be attained by the height of the filter bed being subdivided by one or more vertically spaced groups of sealing strips, in which the sealing strips of each group are disposed in parallel vertically spaced relation at a gradient. The lengths of the sealing strips in each group can be graded in such manner that the lowermost sealing strip has the greatest length and extends to about the middle of the dam. The drainage channels thus defined by the sealing strips can be in communication with separate drainage compartments provided at a single location in the upstream toe wall. Thus, the leakage water collecting on the individual sealing-strip steps of each group may be separately collected and drained off.

The sealing strips in individual groups of sealing strips are provided in the form of watertight foils, for example made of a resistant synthetic resin, e.g., phenol formaldehyde plastic strips, whole longitudinal edges engage in a watertight manner in the material of the core packing adjacent the filter bed. Thus there are formed in the filter wall watertight drainage channels by which the leakage water collected from a particular area is drained off into the associated drainage compartment.

in an alternative construction the sealing strips are formed by layers of the material used for the core packing, which layers extend transversely through the filter wall.

One suitable method of inserting the core packing comprises depositing the materials in horizontal layers in which the materials used for the core packing, the filter wall, and for the adjacent downstream and upstream embankments are disposed side by side. The materials are deposited simultaneously and progressively in the direction of width of the dam, to a substantially uniform level using partitions which separate the materials before deposit and which are advanced ground in the direction of the work. The fills of materials are deposited adjacent each other behind the partitions as considered in the direction of movement, and are simultaneously compacted.

Apparatus suitable for carrying out the method comprises two parallel, upright partitions which are spaced apart at a distance corresponding to the thickness of the core packing, means for advancing the partitions on the ground in the longitudinal direction of the dam, means for depositing and levelling the building material for the downstream and upstream embankments externally of the partitions, means for inserting and levelling the material of the core packing between the partitions, and compacting devices provided behind of the parti tions, as considered in the direction of movement, for simultaneous compression of the separately deposited and levelled materials. Two additional partitions extending parallel to the aforementioned partitions are provided. The additional partitions are spaced apart a distance corresponding to the thickness of the filter wall, and means for inserting and levelling the filter material between the additional partitions are also provided. Further, reciprocating compacting devices for compressing the filter material simultaneously with the compacting of the other building materials are also provided behind of said additional partitions.

The groups of sealing strips formed by watertight foils are inserted as follows. As the core packing is inserted in layers, the foils the width of which suitably exceeds the thickness of the filter bed are simultaneously placed on the immediately preceding layer of the core packing at the desired level of the dam in such manner that they cover the filter bed and their longitudinal edges rest on the adjacent layers of the core packing, whereupon the next layer of the core packing is placed on the foil. Thus, each individual foil is deposited with its longitudinal edges embedded in watertight manner in the adjacent building material used for the core packing on both sides of the filter wall. In similar manner, the next foil in a group of sealing strips is inserted at the desired vertical distance from the foil first laid.

The insertion of the sealing strips in the form of layers of the material used for the core packing can be carried out by charging packing material into the means used for inserting and levelling the filter material. Layers of packing material cohering with the layers of the core packing on both sides and extending transversely through the filter bed are thus directly formed.

The required angle of inclination of the sealing strips in the longitudinal direction of the dam is obtained simply by inserting the layers of the core packing and the adjacent layers of the embankment at the angle of inclination of the gradient.

embodying "the invention, in which the filter bed extends downwardly as far as: to the upstream toe wall, or

cut-off, wall.

A1 separate filter layer or wall in the interior of core packing canbeprovidedfor dams with a high downstream backwash of water or with a high level of ground water. Such ase'parate filter wall can extend up to thehighest level of the backwash. The downstream section'thus defined can be communicatedwith separate chambers provided in the upstream toe wall, and can beprovided with groups of sealing strips in the manner hereinbefore described, by which the leakage water collected thereby isdrained laterally into separate drainage compartments. This construction of the lower part of the core packing facilitates a ready detection of leaks inthat part of the core packing that is below the surface ofthe downstream backwash water and also'makes it possible to determine whether such leak is in the upstream or in the downstream part of the core packing.

A dam embodying the invention is diagrammatically illustrated, by way of example, in the accompanying drawings,in which:

FIG. 1 shows a section over the width of a dam, through a central filter bed in core packing of the dam, inwhich the leakage water seeping into the filter bed through leaks in the core packing is drained through drainage chambers provided in that part of the upstreamtoe wall that is disposed at the bottom of a valley in which the dam is situated;

FIG. 2 shows a corresponding longitudinal section through adam, in which the leakage water seeping through leaks in the core packing into the filter bed is collected and drained by sealing strips provided in the strips provided in the form of synthetic resin foils in the zone of the filter bed;

FIG. 6 shows a cross-section through the core packing on a line such as line V-V in FIG. 2., for construction in which the sealing strips embedded in the filter bed are made of the same material as the core packing; FIG. 7 shows asection on the line VIIVII of FIG. 2;

FIG.*8 shows a longitudinal section of apparatus for producing the core'packing and taken on the line VIII ---VIII of FIG. '9;

FIG. 9 is a planview of the apparatus'illustrated in FIG. 8; and

FIG. 10 shows across-section on the X-X of FIG. 8. t

Referring to the drawings, it will be notedin FIG. 3, which shows a detail of FIG. 1, that a filter wall 2 is provided in the interior of a core packingl. Thefilter wall 2 extends in the longitudinal direction of the core packing along the whole longitudinal section thereof down to an upstream toe wall 4 by which the core packing is supported. The filter wall 2 and downstream and upstream sections 'la andlb of the core packing form an integral body which is intimately interlocked by interengaging mineral particles. The sealing sections la and lb of the core packing are distinguished from the filter bed substantially only by the fact that the cavities of the matrix of mineral particles in the packing sections la and lb are filled with a watertight mortar, for example with bitumen, whereas the cavities in the filter. bed are open. This uniform core-packing body is intimately in terlockedor otherwise interconnected with the adjacent downstream and upstream embankments 5a and 5b. In operation, the upstream section la serves as the sealing apron, in which leaks are to be detected.

Thefilter bed 2 is in communication with a plurality of leakage-water collectors or drains in the form of drainage chambers or compartments 6, 7, 8, and 9 providedin the upstream toe wall 4. The. drainage com- .partments 6, 7, 8 and 9, which are provided at as regular intervals aspossible along that section of the upstream toe wall that extends at the bottom of the valley, are covered at the top with gratings. Connected to the drainage compartments 6, 7, 8, and 9 are pipe lines 10,.

ll, 12 andl3 respectively, which either emerge on the downstream face of the dam or open out into a control and measuring shaft (not shown) provided on the downstream face of th dam. By virtue of this construction, the core packing is directly subdivided into a series of several vertical control sections Klto K4 which are shown by dash-and-dot 'lines in FIGS. 1 and 2 of the drawings, andfroin which the leakage water seeping into the filter bed through leaks in the core packing in the zone of the individual control sections is drained off downwardly into the associated drainage collectors or compartments. By watching the volumes of leakage water flowing off through the pipe lines 10 to 13 it can thus be checked in what particular control section a leak has occurred andwhether such leak requires repairing upon the occurrence of a corresponding volume of leakage water.

Thus, in the embodiment of FIG. 1, the filter-wall is continuous over the height of the dam, for vertical drainage through thefilter-wa ll to the toe wall. The collectors are disposed at spaced intervals over the width of the dam thereby providing a division of the filter wall into a plurality of vertical sections each extending over the height of the filter wall and communicating with a collector.

Where high dams are involved, the vertical control sections may advantageously be subdivided in order to facilitate an adequatelyaccurate location of theposition at which a leak has occurred; In order to facilitate the location of leaks, the height of the filter bed is subdivided by one or more groups 14 of longitudinally extending sealing strips 14a to 14d (FIGS. 2, S and 6). The sealing strips are disposed in the filter-wall, and formwatersheds for respective vertical sections of the filter-wall, and communicate the respective vertical sections with their respective collectors. The sealing strips extend in parallel vertical spaced relation (x) at a gradient in the direction of that part of the upstream toe wall that extends on the slope of the valley, their lengths within a groups being graded so that the respectively lowermost sealing strip 14a having the greatest length extends substantially to a mid-position of the dam. The outer end of strip 14a, uncovered by strip 14b, forms a watershed for section k of the filter wall. The sealing strips form the boundaries of drainage channels 15a to [5c in the filter bed, the individual drainage channels conducting the leakage water collecting on the projecting surface of the respective sealing strip below them in the direction of the upstream toe wall 4 into the respective drainage compartment 16a to 16d in the upstream toe wall as indicated by arrows, the individual drainage chambers being respectively provided with drain pipes 17a to 17d. The drain pipes may either emerge on the downstream face of the dam or they may open out into a control and measuring shaft, not shown in the drawings. The groups of sealing strips 14a to 14d subdivides the large control sections Kl K4 (FIG. 1) into a plurality of small control sections kl k4 and k5 k8, the width b of which corresponds to the width b (FIG. 2) of the steps or watersheds formed by the sealing strips 14. The core packing may be subdivided into any optional number of control sections kl to kx of any optional small dimensions by inserting several groups of sealing strips at various levels of the dam. The leaks in the core packing can thus be located with utmost precision, their removal involving little expenditure or work.

The use of sealing strips facilitates locating the collectors at a common location. That simplifies the observation of leakage.

The groups of sealing strips hereinbefore described may be used in the core packing which is subdivided into vertical control sections as illustrated in FIG. 1. Instead of the subdivision obtained by a plurality of drainage chambers in the upstream toe wall as illustrated in FIG. 1, a subdivision may also be obtained by means of sealing strips 180 to 18 located adjacent the toe wall and which extend in parallel vertical spaced relation at an inclination to the lowermost point of the dam, the lengths of the sealing strips in each group being graded so that the respectively lowermost sealing strip has the greatest length. Drainage channels 19a to 19c thus defined in the filter bed are in communication with separate drainage collectors or chambers 20a and 20d at the lowermost point of the upstream toe wall, as illustrated in FIG. 2, the individual drainage chambers being respectively provided with drain pipes 21a to 21d for checking the leakage water flowing off from the individual control sections kl to k4 (FIG. 7). As compared with the construction illustrated in FIG. 1, this construction affords the advantage that all of the drain pipes are disposed in direct close juxtaposition at the lowermost position of the dam where they can be readily checked in a common small control shaft. See FIG. 7.

Thus, the filter wall can be continuous over the height thereof for vertical drainage through the filter wall to adjacent the toe wall, and vertically spaced sealing strips can be disposed in the filter wall adjacent the toe wall forming watersheds for respective vertical sections of the filter wall, and the watersheds can be communicated with the collectors.

Alternatively, a first group of collectors can be communicated respectively with sections in the lower part of the filter wall, while a second group of collectors is communicated with sections in the upper part of the filter wall. Sealing strips separate the upper and lower sections. Further, as is illustrated in FIG. 2, additional sealing strips can be disposed in the filter wall adjacent the toe wall forming watersheds for the respective lower sections and communicating the respective lower sections with collectors.

As illustrated in FIG. 5, the sealing strips 14 and 18 may be formed by watertight synthetic resin foils the longitudinal edges of which engage in a watertight manner in the material of the adjacent sections la and lb of the core packing. However, as shown in FIG. 6, the sealing strips may also be formed of layers of the material used for the core packing, which layers extend transversely through the filter bed and merge into the the adjacent sections 1a and 1b of the core packing.

In dams with a higher downstream water backwash or ground-water level, the lower part of the core packing is constructed as illustrated in FIG. 4. The drawing shows that the filter layer 2 extends beyond the highest water backwash level (ST) subdivided in the longitudinal direction of the dam by a sealing apron or curtain 22 which is preferably made of the same sealing material as the core packing. The top of the sealing curtain or apron 22 is connected to the downstream section of the core packing and thus defines a downstream section 2b of the filter wall,'i.e., a second filter wall 2b. As described with reference to FIG. 1, the upwardly extending upstream part 2 of the filter bed rests on the drainage chambers 6, 7, 8 and 9 provided in the upstream toe wall, the downstream section 2b of the filter bed resting on its own drainage collectors or chambers adjacent the drainage chambers 6 to 9 but separate therefrom and being provided with its own drain pipes which may either emerge on the downstream face of the dam or may open out into the control shaft referred to and are thus accessible to inspection. Thus, for example, drainage chambers 6' associated with the downstream section 2b of the filter bed and a drain pipe 10 thereof are shown in FIG. 4. It will be understood that groups of sealing strips for draining the leakage water may be provided in the manner hereinbefore described in the downstream section 2b of the filter bed. This construction of the core packing section disposed below the highest backwash water level facilitates a ready detection of leaks occurring in any one of control sections kl kx in the upstream section la of the core packing or in the downstream section lb of the core packing.

The core packing may be constructed in layers at any angle of inclination without difficulty as the dam is banked up in layers. Apparatus for insertion of the core packing in layers is illustrated in FIGS. 8 to 10.

The apparatus comprises essentially (a) two parallel upright partitions 23 and 23' which are spaced apart at a distance corresponding to the thickness of 'the core packing l, and (b) two further parallel upright partitions 24 and 24 extending between the first partitions 23 and 23' parallel thereto, the space between the partitions 24 and 24' corresponding to the thickness of the filter layer 2. The partitions, which are made of steel plate, are securely interconnected by cross-ties in order to maintain them in parallel relation. The bottom edges of the partitions, which rest closely on the levelled ground, are fed at the necessary operating speed in the longitudinal direction of the dam under construction, the direction of feed being indicated by an arrow in FIGS. 8 and 9.

The front part (on the left as seen in FIGS. 8 and 9) of the parallel partitions 23 and 23' has a saddle roof 25 by which the space between the partitions is covered, and an angular breaching plate 26 similar to a ships bow in front. A scraper blade 27 adapted to be raised and lowered and extending transversely across the partitions 23 and 23' moves on the two outside surfaces of the partitions.

Each of the two pairs of partitions 23 and 23', and 24 and 24' is provided with a supply bin or hopper 28 and 29 for the building material. Outlets of the bin 28, which is filled with the material for the packing, opens into the lateral spaces adjacent the partitions 24 and 24' and between the partitions 23 and 23, whilst an outlet of the bin 29, which is filled with the material for the filter layer or bed, opens into the space between the partitions 24 and 24' (FIG. Vertically adjustable regulating slides or gates 30, 31 and 30, by which the height of the layer of material between the partitions is determined, are provided beyond the bins and between the partitions 23, 24, 24 and 24', and 24' and 23 respectively.

A yoke 32 to which a plurality of reciprocating compacting devices 33 and 33', 34 and 34, and 35 are attached, is secured to the ends of the parallel partitions. The two compacting devices 33 and 33' operate in the zone of lateral embankments a and a levelled by the scraper blade 27, the compacting devices 34 and 34', and 35, operating in the zone of the layers b and b, and 0 respectively of packing and filter materials applied by the bins 28 and 29. Where the material used for the packing is combined with a bituminous material, the compacting devices 34 and 34 are provided with heated base plates in order. to prevent adhesion of the bituminous material for the packing.

As the apparatus with its parallel partitions 23 and 23, 24 and 24' advances in the direction of the arrow in FIG. 8 and FIG. 9, the material for the downstream and upstream embankments, which material generally consists of coarse rock, is poured on to the roofedover part 25 of the partitions forwardly of the scraper blade 27, for example by a grab excavator 36. The material deposited outwardly ofthe partitions 23 and 23' slopes down to the zone of the scraper blade 27 by which it is levelled to a determined height in a layer of height about to cm. as shown in FIG. 1. Simultaneously, packing material from the bins 28 and filter material from the bin 29 pass into the associated spaces between the outer partitions 23 and 24 and between the two internalpartitions 24 and 24, and also into the space between the partitions 24 and 23, as illustrated in FIG. 10, to be levelled to substantially the same height as the embankments externally of the partitions. The layers thus deposited separately by the partitions lie directly adjacent each other in the zone of the compacting devices 33 and 33', 34 and 34' and 35 by which they are simultaneously and uniformly compressed or compacted. The seams of adjacent layers are respectively disposed between two adjacent compacting devices. In the zone of the seams the supporting mineral particles of adjacent layers are thus pressed against each other 10 so that they merge and are consequently firmly interlocked. The dam is banked up layer by layer in the manner hereinbefore described as indicated by dashdot lines in FIG. 10. Owing to the close interlocking of the layers and their seams, a uniform, supporting mineral matrix is formed by which the filter bed is connected to the adjacent layers of the'packing and by which the layers of the packing are connected to the lateral embankments, the desired interlocking between the internal packing and the supporting layers on both sides of the dam thus being ensured.

Where a bituminous material is used for the core packing, a sealed connection between adjacent, horizontally extending layers may be ensured by providing radiators 37 and 37', for example infra-red radiators, in the front part, or left hand part as seen in FIG. 9, of the apparatus between the partitions 23 and 23', the radiators radiating their heat to the layers of bituminous material compressed during the preceding operation thus softening them to a depth of about 2 to 3 cm. immediately before the next layer is applied.

The sealing strips, such as 14b in FIG. 2, formed by synthetic resin foils are inserted by placing them on the layer just inserted after which the next layer is poured on to the strips. For insertion of sealing strips which are made of the same material as the core packing, as in FIG. 6, the supply bin 29 is charged with core-packing material instead of being charged with filter material as the apparatus moves a distance corresponding to the desired length of the sealing strip. In orderto provide sloping sealing strips, the'horizontally extending layers can be laid up with a slope.

The core packing in the interiorofdams proposed comprises one or more vertically extending filter layers for checking the imperviousness of the core packing and requires no control packing which may be endangered by settling movements of the dam. The control system of the core packing, which is subdivided into an optional number of control sections, is not subject to any danger arising from settling movements of the dam.

What is claimed is:

I. In a dam comprising a core packing providing a sealing apron, upstream and downstream embankments lateally supporting the core packing, and a foundation toe wall along the bottom of the darn vertically supporting the core packing, a filter wall vertically supported by the toe wall, laminated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors means communicating the leakage water collectors respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received at the collectors, the improvement which comprises said communicating means comprising a group of vertically spaced sealing strips disposed longitudinally in the filter wall, the length of the strips increasing successively from the uppermost to the lowermost forming watersheds for respective vertical sections of the filter wall and channels between adjacent strips communicated with respective collectors.

2. A dam according to claim 1, the collectors being located at a common location for facilitating observa' tion of leakage.

3. A dam according to claim 2, the filter wall being continuous over the height thereof for vertical drainage through the filter wall to adjacent the toe wall, said sealing strips being disposed adjacent the toe wall.

4. A dam according to claim 1, said plurality of collectors forming a first group of collectors, said first group of collectors being communicated respectively with sections in the lower part of the filter wall, a second group of collectors communicated with sections in the upper part of the filter wall, additional sealing strips separating said lower and upper sections, said additional sealing strips being disposed longitudinally in the filter wall in vertically spaced relation the length of the strips increasing successively from the uppermost to the lowermost forming watersheds for the respective upper sections and communicating the respective upper sections with the respective collectors of said second group of collectors.

5. A dam according to claim 4, the second group of collectors being located at a common location for facilitating observation of leakage.

6. A dam according to claim 4, the collectors of each group of collectors being located at a common location for facilitating observation of leakage.

7. A dam according to claim 1, the sealing strips being plastic having both longitudinal edges in watertight engagement the core packing and extending transversely through the filter wall.

8. A dam according to claim 1, the sealing strips being formed by material forming the core packing and extending transversely through the filter wall.

9. A dam according to claim 1, and a second filter wall disposed on the downstream side of the first filter wall, both filter walls being embedded within the core packing, said second filter wall being for receiving leakage of backwash or ground water through the core packing at about the location where leakage occurs, and a second plurality of leakage water collectors, communicated respectively with different sections of the second filter wall for receiving leakage respectively from said sections of the second filter wall, whereby location of leakage of backwater is detectable by observation of water received at the collectors for the second filter wall.

10. A dam according to claim 9, the filter walls being divided by a sealing apron disposed between the filter walls and made of the same material as that used for the core packing, the dividing apron being connected at the top to the downstream section of the core packing.

11. A method for constructing a dam according to claim 1, of inserting a core packing having a filter wall laminated therewith, in layers during construction of the dam, in which materialused for the core packing and material used for downstream and upstream faces of the dam or embankment are progressively and simultaneously deposited spatially separately in the longitudinal direction of the dam by parallel vertical or inclined partitions advancing in the direction of the work and are levelled to substantially the same level, material used for the filter wall in the core packing being deposited together with the other building material spatially separately from the material used for the core packing and pregressively in the direction of the dam, two substantially parallel vertical or inclined partitions moving on the levelled ground in the direction of the work, the material for the filter wall or bed being then levelled to substantially the same level as the other building material and the fills of material for the filter wall and/or packing, which fills lie directly adjacent 12 each other beyond the partitions in the direction of movement of the partitions, and the fills of the packing material, filter wall, and of the lateral embankments, being simultaneously compacted.

12. A method according to claim 1 l, in which sealing strips are provided in the filter wall, in the form of synthetic resin foils, the core packing being inserted in layers, the foils forming the sealing strips, the width of which exceeds the thickness of the filter bed, being simultaneously placed at the desired level of the dam upon the layer of core packing just inserted, so that they cover the filter bed, and their longitudinal edges rest on the adjacent layers of the core packing, whereupon the next layer of the core packing is deposited on the foil.

13. A method according to claim 1 l, in which sealing strips made of the same material as the core packing are inserted in the filter wall, the sealing strips extending transversely through the filter wall.

14. A dam according to claim 3, the collectors being disposed in the central lower part of the dam, the dam having two groups of sealing strips, each group being as aforesaid, one group being disposed on each side of the center of the dam, the respective groups being inclined downwardly from the sides of the dam to the center thereof providing the channels between the strips in communication with the collectors.

15. A dam according to claim 4, said first group of collectors being disposed in the central lower part of the dam, the dam having two lower groups of sealing strips each lower group being as aforesaid, one lower group being disposed on each side of the center of the dam, the respective lower groups being inclined downwardly from thesides of the dam to the center thereof providing the channels between the strips in communication with the first group of collectors, said second group of collect-ores comprising two sub-group of collectors, one sub-group being disposed on each side of the dam, said additional sealing strips comprising two upper groups of sealing strips, each upper group being as aforesaid, one upper group being disposed on each side of the center of the dam, the respective upper groups being inclined downwardly from the center of the dam to the sides thereof providing the channels between the strips in communication with one of said subgroups of collectors.

16. Apparatus for constructing a darn according to claim 1, for inserting a core. packing in layers during construction of the dam, comprising two substantially parallel inclined or upright partitions which are spaced apart at a distance corresponding to the thickness of the core packing, means for feeding the partitions on levelled ground in the longitudinal direction of the dam, means for depositing and levelling the building material for downstream and upstream faces of the dam externally of the partitions, means for inserting and levelling the material used for the core packing between the partitions, and reciprocating compacting devices for the simultaneous compacting of separately deposited and levelled building materials, which reciprocating compacting devices are provided behind the partitions as considered in the direction of movement, there being between the first partitions further partitions extending parallel to the first partitions and to each other, the second partitions being spaced apart at a distance corresponding to the thickness of the filter wall, means for inserting and levelling the filter material for the filter wall being provided between the second partitions, there also being a compacting device capable of compacting the filter material simultaneously with the other building materials being provided behind the second partitions as considered in the direction of movement of the partitions.

17. In a dam comprising a core packing providing a sealing apron, upstream and downstream embankments laterally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing, the improvement for detecting location of leaks in the sealing apron, which comprises a filter wall vertically supported by the toe wall, laminated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors, communicated respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received .at the collectors, said plurality of collectors forming a first group of collectors, said first group of collectors being communicated respectively with sections in the lower part of the filter wall, a second group of collectors communicated with sections in the upper part of the filter wall, sealing strips separating said lower and upper sections, said sealing strips being disposed in the filter wall in vertically spaced relation forming watersheds for the respective upper sections and communicating the respective upper sections with the respective collectors of said second group of collectors.

18. A darn according to claim 17, the second group of collectors being located-at a common location for facilitating observation of leakage.

19. A dam according to claim 17, and additional vertically spaced sealing strips, said additional strips being disposed in the filter wall adjacent the toe wall forming watersheds for the respective lower sections and communicating the respective lower sections with respective collectors of the first group of collectors.

20. A dam according to claim 19, the collectors of each group of collectors being located at a common lo cation for facilitating observation of leakage.

21. Method of constructing a dam comprising a core packing providing a sealing apron, upstream and downstream embankments laterally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing, a filter wall vertically supported by the toe wall, laminated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors communicated respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received atthe collectors, said method comprising inserting the core packing having the filter wall laminated therewith, in layers during construction of the dam, in which material used for the core packing and material used for downstream and upstream faces of the dam or embankment are progressively and simultaneously deposited spatially separately in the longitudinal direction of the dam by parallel vertical or inclined partitions advancing in the direction of the work and are levelled to substantially the same level, material used for the filter wall in the core packing being deposited together with the other building material spatially separately from the material used for the core packing and progressively in the direction of the dam, two substantially parellel vertical or inclined partitions moving on the levelled ground in the direction of the work, the material for the filter wall or bed being then levelled to substantially the same level as the other building material and the fills of material for the filter wall and/or packing, which fills lie directly adjacent each other beyond the partitions in the direction of movement of the partitions, and the fills of the packing material, filter wall, and of the lateral embankments, being simultaneously compacted.

22. A method according to claim 21, in which sealing strips are provided in the filter wall, in the form of synthetic resin foils, the core packing being inserted in layers, the foils forming the sealing strips, the width of which exceeds the thickness of the filter bed, being simultaneously played at the desired level of the dam upon the layer of core packing just inserted, so that they cover the filter bed, and their longitudinal edges rest on the adjacent layers of the core packing, whereupon the next layer of the core paclking is deposited on the foil.

23. A method according to claim 21, in which sealing strips made of the'same material as the core packing are inserted in the filter wall, the sealing strips extending transversely through the filter wall. 

1. In a dam comprising a core packing providing a sealing apron, upstream and downstream embankments lateally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing, a filter wall vertically supported by the toe wall, laminated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors means communicating the leakage water collectors respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received at the collectors, the improvement which comprises said communicating means comprising a group of vertically spaced sealing strips disposed longitudinally in the filter wall, the length of the strips increasing successively from the uppermost to the lowermost forming watersheds for respective Vertical sections of the filter wall and channels between adjacent strips communicated with respective collectors.
 2. A dam according to claim 1, the collectors being located at a common location for facilitating observation of leakage.
 3. A dam according to claim 2, the filter wall being continuous over the height thereof for vertical drainage through the filter wall to adjacent the toe wall, said sealing strips being disposed adjacent the toe wall.
 4. A dam according to claim 1, said plurality of collectors forming a first group of collectors, said first group of collectors being communicated respectively with sections in the lower part of the filter wall, a second group of collectors communicated with sections in the upper part of the filter wall, additional sealing strips separating said lower and upper sections, said additional sealing strips being disposed longitudinally in the filter wall in vertically spaced relation the length of the strips increasing successively from the uppermost to the lowermost forming watersheds for the respective upper sections and communicating the respective upper sections with the respective collectors of said second group of collectors.
 5. A dam according to claim 4, the second group of collectors being located at a common location for facilitating observation of leakage.
 6. A dam according to claim 4, the collectors of each group of collectors being located at a common location for facilitating observation of leakage.
 7. A dam according to claim 1, the sealing strips being plastic having both longitudinal edges in watertight engagement the core packing and extending transversely through the filter wall.
 8. A dam according to claim 1, the sealing strips being formed by material forming the core packing and extending transversely through the filter wall.
 9. A dam according to claim 1, and a second filter wall disposed on the downstream side of the first filter wall, both filter walls being embedded within the core packing, said second filter wall being for receiving leakage of backwash or ground water through the core packing at about the location where leakage occurs, and a second plurality of leakage water collectors, communicated respectively with different sections of the second filter wall for receiving leakage respectively from said sections of the second filter wall, whereby location of leakage of backwater is detectable by observation of water received at the collectors for the second filter wall.
 10. A dam according to claim 9, the filter walls being divided by a sealing apron disposed between the filter walls and made of the same material as that used for the core packing, the dividing apron being connected at the top to the downstream section of the core packing.
 11. A method for constructing a dam according to claim 1, of inserting a core packing having a filter wall laminated therewith, in layers during construction of the dam, in which material used for the core packing and material used for downstream and upstream faces of the dam or embankment are progressively and simultaneously deposited spatially separately in the longitudinal direction of the dam by parallel vertical or inclined partitions advancing in the direction of the work and are levelled to substantially the same level, material used for the filter wall in the core packing being deposited together with the other building material spatially separately from the material used for the core packing and pregressively in the direction of the dam, two substantially parallel vertical or inclined partitions moving on the levelled ground in the direction of the work, the material for the filter wall or bed being then levelled to substantially the same level as the other building material and the fills of material for the filter wall and/or packing, which fills lie directly adjacent each other beyond the partitions in the direction of movement of the partitions, and the fills of the packing material, filter wall, and of the lateral embankMents, being simultaneously compacted.
 12. A method according to claim 11, in which sealing strips are provided in the filter wall, in the form of synthetic resin foils, the core packing being inserted in layers, the foils forming the sealing strips, the width of which exceeds the thickness of the filter bed, being simultaneously placed at the desired level of the dam upon the layer of core packing just inserted, so that they cover the filter bed, and their longitudinal edges rest on the adjacent layers of the core packing, whereupon the next layer of the core packing is deposited on the foil.
 13. A method according to claim 11, in which sealing strips made of the same material as the core packing are inserted in the filter wall, the sealing strips extending transversely through the filter wall.
 14. A dam according to claim 3, the collectors being disposed in the central lower part of the dam, the dam having two groups of sealing strips, each group being as aforesaid, one group being disposed on each side of the center of the dam, the respective groups being inclined downwardly from the sides of the dam to the center thereof providing the channels between the strips in communication with the collectors.
 15. A dam according to claim 4, said first group of collectors being disposed in the central lower part of the dam, the dam having two lower groups of sealing strips each lower group being as aforesaid, one lower group being disposed on each side of the center of the dam, the respective lower groups being inclined downwardly from the sides of the dam to the center thereof providing the channels between the strips in communication with the first group of collectors, said second group of collect-ores comprising two sub-group of collectors, one sub-group being disposed on each side of the dam, said additional sealing strips comprising two upper groups of sealing strips, each upper group being as aforesaid, one upper group being disposed on each side of the center of the dam, the respective upper groups being inclined downwardly from the center of the dam to the sides thereof providing the channels between the strips in communication with one of said sub-groups of collectors.
 16. Apparatus for constructing a dam according to claim 1, for inserting a core packing in layers during construction of the dam, comprising two substantially parallel inclined or upright partitions which are spaced apart at a distance corresponding to the thickness of the core packing, means for feeding the partitions on levelled ground in the longitudinal direction of the dam, means for depositing and levelling the building material for downstream and upstream faces of the dam externally of the partitions, means for inserting and levelling the material used for the core packing between the partitions, and reciprocating compacting devices for the simultaneous compacting of separately deposited and levelled building materials, which reciprocating compacting devices are provided behind the partitions as considered in the direction of movement, there being between the first partitions further partitions extending parallel to the first partitions and to each other, the second partitions being spaced apart at a distance corresponding to the thickness of the filter wall, means for inserting and levelling the filter material for the filter wall being provided between the second partitions, there also being a compacting device capable of compacting the filter material simultaneously with the other building materials being provided behind the second partitions as considered in the direction of movement of the partitions.
 17. In a dam comprising a core packing providing a sealing apron, upstream and downstream embankments laterally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing, the improvement for detecting location of leaks in the sealing apron, which comprises a filter wall vertically supported by the toe wall, lamInated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors, communicated respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received at the collectors, said plurality of collectors forming a first group of collectors, said first group of collectors being communicated respectively with sections in the lower part of the filter wall, a second group of collectors communicated with sections in the upper part of the filter wall, sealing strips separating said lower and upper sections, said sealing strips being disposed in the filter wall in vertically spaced relation forming watersheds for the respective upper sections and communicating the respective upper sections with the respective collectors of said second group of collectors.
 18. A dam according to claim 17, the second group of collectors being located at a common location for facilitating observation of leakage.
 19. A dam according to claim 17, and additional vertically spaced sealing strips, said additional strips being disposed in the filter wall adjacent the toe wall forming watersheds for the respective lower sections and communicating the respective lower sections with respective collectors of the first group of collectors.
 20. A dam according to claim 19, the collectors of each group of collectors being located at a common location for facilitating observation of leakage.
 21. Method of constructing a dam comprising a core packing providing a sealing apron, upstream and downstream embankments laterally supporting the core packing, and a foundation toe wall along the bottom of the dam vertically supporting the core packing, a filter wall vertically supported by the toe wall, laminated with the core packing, and for receiving leakage of the core packing at about the location where leakage occurs and a plurality of leakage water collectors communicated respectively with different sections of the filter wall for receiving leakage respectively from said sections, whereby location of leaks is detectable by observation of water received at the collectors, said method comprising inserting the core packing having the filter wall laminated therewith, in layers during construction of the dam, in which material used for the core packing and material used for downstream and upstream faces of the dam or embankment are progressively and simultaneously deposited spatially separately in the longitudinal direction of the dam by parallel vertical or inclined partitions advancing in the direction of the work and are levelled to substantially the same level, material used for the filter wall in the core packing being deposited together with the other building material spatially separately from the material used for the core packing and progressively in the direction of the dam, two substantially parellel vertical or inclined partitions moving on the levelled ground in the direction of the work, the material for the filter wall or bed being then levelled to substantially the same level as the other building material and the fills of material for the filter wall and/or packing, which fills lie directly adjacent each other beyond the partitions in the direction of movement of the partitions, and the fills of the packing material, filter wall, and of the lateral embankments, being simultaneously compacted.
 22. A method according to claim 21, in which sealing strips are provided in the filter wall, in the form of synthetic resin foils, the core packing being inserted in layers, the foils forming the sealing strips, the width of which exceeds the thickness of the filter bed, being simultaneously played at the desired level of the dam upon the layer of core packing just inserted, so that they cover the filter bed, and their longitudinal edges rest on the adjacent layers of the core packing, whereupon the nexT layer of the core packing is deposited on the foil.
 23. A method according to claim 21, in which sealing strips made of the same material as the core packing are inserted in the filter wall, the sealing strips extending transversely through the filter wall. 